Analysis of misdiagnosis of xanthogranulomatous pyelonephritis

Objective To improve the diagnosis and treatment of xanthogranulomatous pyelonephri- tis(XGP).Methods The clinical data of 18 cases(5 males and 13 females;mean age,47 years)with XGP were analyzed.Of them,6 had the lesion on the left,and 12 on the right.Before operation,XGP was mis- diagnosed as renal calculus with hydronephrosis in 4 cases,ureteral calculus with severe hydronephrosis in 3 cases,renal tuberculosis in 3 cases and renal carcinoma in 8 cases.Results Of the 18 cases,7 were diag- nosed to have XGP by frozen section during operation and 11 cases had a definite diagnosis by pathological examination after nephrectomy.After a follow-up of 6-124 months,no recurrence was observed in all these 18 cases.Conclusions Preoperative diagnosis of XGP is difficult.This disease is clinically characterized by foam cells in urine smear,low-density value of kidney CT and ineffective antibiotic therapy.Combined a- nalysis of clinical data and improvement of clinical recognition of XGP is the key to avoiding delayed diagno- sis or misdiagnosis of XGP.